The following sources are totally ignored. The life of Vita Anskarii , (actually contemporary with Rurik), and The Nestors chronicle. Why? Are ther a tons of sources left to consider? No!
As I stated before, this was a time when people lived in a very regulated caste society, meaning that nobody could become anything no matter what he did than he was destined to be. A fisherman could never become a king, a simple small farmer neither, nor a slave or any young man who joined a viking trip unless he had the right bloodlines.
People were either slaves or free men, the later ones were the same who were a part of the hierarchy in a very social stratified community.
You can not apply a modern view to this, men who by their own effort made their own fortune or become extremely successful are conspicuously absent in the medieval history sources, and not without reason.. And that how it worked back then, and that how it still worked when Jean Bernadotte become the king in Sweden, he had to first be adopted by the former king, than have his new name Karl XIV Johan.
The first thing they did was to let his children marry in to the Swedish nobility, thus making them by blood became more legit. This nothing new, this just follow how things did work. You are free to have your own belief, but how accurate they are are something else.
Summary
1* Someone have tried their best to rewrite the history, not once but several times over and over. The Kings in Svitjod are actually still called fairy kings although they are referred in several different ancient historical texts as real kings.
2* In the 850, King Olof ruled in Svitjod when Ansgar arrived to Birka again to reestablish the christian parish, (852). Olof was believed to be a son of Björn at Håga.
3 * In the life of "Vita Anskarii", it is told that Olof led a war expeditions against people in the east that had previous been ruled by them but had broken free because they did not accepted the Svitjod supremacy in the beginning of 800.
4* This event correlated with that Nestor later reproduces in his chronicle, telling the story of emissaries chosen from different tribes to represent the slaves, sent to ask the Rus leaders to take back control in their area. Nestor doesn't really pin point this event, but commonly the year 862 have been chosen, but it is only one estimate, consider that archaeologists estimates that the graves in Novgorod started to be used approximately from the year 850.
5* Most likely Rurik was the son of Olof and the great picture becomes as following, sometime under the middle of 800 century, Olof ruled as King in Svitjod, he was asked to help the people in east to take back control, which he did starting by attacking Kurland, then moving around that area, at the same time danish vikings tried to plunder this areas leading to conflicts and battle with them, ending with that they finaly got rid of the danes, this is also the reason WHY Rurik wasn't of direct danish origin, more likely, or in fact the only possible solution is that Rurik was indeed the son of Olof and that he was ordered to take control of the more northern part east of Kurland, now known as Novgorod, while his two other brothers were sent away in two other directions, not surviving their mission resulting that only Rurik were successful.
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Note
Ansgar died 865, Vita Anskarri was written by his successor Rimbert
under the period of 865-876, so when he mentioned that Olof led a war expedition against Kurland, he should be considered as a contemporary source retelling an event based on historical facts, not fiction.
Secondly, it definitively stated that the danish vikings did plunder. Sporadic raids to gain personal profit are not the same as defeating the opposition against the Svitjod's supremacy, and it's definitively not the same thing as taking control over and of the land or trying to establish some kind of order, it's in fact the opposite.
Now, feel free to talk about historical revisionism..